06 Pacifica keeps going into Limp In Mode
 

06 Pacifica 3.5L, 215,000 miles

I had this happen one time 4 years ago and it was resolved when we replaced the battery, alternator and starter. No telling what the real issue was.

This time, the car will get stuck in second gear, cannot shift in manual mode and it will only do reverse and 2nd. I have tried resetting (battery undone for a while) but that did not seem to work
Then I tried charging the battery, even though it seemed plenty strong. After charging the battery to full, the car would shift normally for several days then it happens again.
So, I'm wondering if this is related to a bad alternator? I do not get the speedometer jumps that people talk about with a bad diode alternator. However the recharging of the battery makes
me think it is somehow electrical. Once it's all reset, the car seems to drive fine, shifts smoothly.
Do not have the codes, unfortunately both of the times I reset with the battery off before checking the codes. Next time, I will definitely pull the codes before trying to reset.

Any insight would be appreciated. I am afraid to venture too far from home as it is.

Whats the voltage across the battery when the engine is running and when the engine is off?

just took it to Advance Auto Parts, they tested the battery, starter and alternator.

Battery tested Good, 12.8V 715 CCA
Starter tested Normal
Alternator tested No Problems No load 14.3v Loaded 14.52V

It did show a Ripple 116mv between -.24v and +.24v

Not sure if that is enough of a Ripple to mess with the tranny sensors?

Ok, given that you replaced the battery 4 years ago, I assume that this is a daily driver, I would consider replacing the battery even though it does appear to be testing ok. Have you taken the battery to a shop for testing at all?

Given that you have already replaced the alternator and the starter only 4 years ago, I can't see those needing replacing again, so I would be looking more to a sensor issue.

Have you checked the terminals on the battery and the alternator to make sure that they are clean? I would also consider checking the wires to the sensors for any damage.

Terminals are clean, Battery tested Good at Advance auto parts.

Well what code(s) does it show?...That will help track things to a sensor OR wire circuit! Poor chassis or engine ground points can do the same bad things as dirty/corroded battery terminal connections too.Trace the neg. cable from the battery to their end connecting points and try cleaning those.

Thanks, I'll chase the grounds and see if that helps.
Unfortunately no codes related to the tranny problem, I had reset Before reading them.
When the codes come back, I'm not driving much, I will post them.